The overall objectives of the proposed research are: (a) To define a set of functional membrane properties of erythroid, lymphoid, and myeloid cells in animal models and in man at different stages in maturation and during neoplastic tranformation. (b) To assess with a set of functional membrane parameters alterations in different cellular components of the immunological defense mechanism. To determine whether this chosen set of functional membrane parameters can contribute to an assessment of immunological competence. (c) The set of membrane parameters include: (1) The permeability coefficient of the cell membrane to water, LP. (2) The permeability coefficients and interaction coefficients of the cell membrane to lipid soluble and insoluble probes omega RT and sigma). (3) The thermodynamic properties of these membrane properties. a) Energies and entropies of activation. (4) Kinetic parameters of electrolyte transport. a) Passive and active components of Na ion and K ion, and Cl ion transport, including, where possible, electrophysiological attributes. Given such a set of membrane parameters as a functional description of the membrane surface, to follow the responses to neoplastic transformation, lymphocytic blastogenesis and the target cell-lymphocyte interaction.